That happened to me, or something similar, with my HP Pavilion dv6. You know that silly picture that covers the password screen -- you click on it and it "rises" out of the way? Well, mine kept going up and down, every time I tried to input my password, blocking the field. After a few hours of restarting I -- shh! I know it's shocking -- deliberately shut off the power while Windows was restarting, hoping to get the Windows rescue screen. But all that happened was a screen that came up with two buttons: one was "restart" and the other was "advanced options", which when clicked did absolutely nothing. I couldn't get to the Startup options menu by hitting "escape", even during the two seconds Windows offered that option. When I hit "escape" it simply ignored it.
I don't know if this is any comfort, but after another couple hours, the computer healed itself. I think it also helped that I plugged in a mouse, rather than using the one installed in the laptop. The computer seemed to ignore the latter, but responded almost instantly to the former. Good luck!